Process for manufacture of artificial leather

ABSTRACT

A PROCESS FOR THE MANUFACTURE OF AN ARTIFICIAL LEATHER, WHICH COMPRISES A FIRST STEP WHEREIN A FLUFF-HOLDING HIGHMOLECULAR-WEIGHT POLYMER IS APPLIED TO THE SURFACE OF A FIBROUS SHEET MATERIAL AND THE SURFACE OF SAID FIBROUS SHEET MATERIAL IS CONTACTED WITH A SMOOTH SURFACE HEATED TO A TEMPERATURE NOT LOWER THAN THE GLASS TRANSITION POINT OF FIBERS THAT CONSTITUTE SAID FIBROUS SHEET MATERIAL BUT NOT HIGHER THAN THE MELTING POINT OF SAID HIGH-MOLECULARWEIGHT POLYMER TO THEREBY HOLD DOWN THE FLUFFS ON THE SURFACE OF THE SHEET MATERIAL AND A SECOND STEP WHEREIN A BINDER SOLUTION AND SUBSEQUENTLY A COATING SYNTHETIC RESIN SOLUTION ARE APPLIED TO SAID FIBROUS SHEET MATERIAL AND THEREAFTER COAGULATED.

United States Patent 3,565,670 PROCESS FOR MANUFACTURE OF ARTIFICIAL LEATHER Toshikazu Shinohara, Ohtsu-shi, Toyohiko Hikota, Kyoto, and Hiroshi Hattori, Ohtsu-shi, Japan, assignors to Toray Industries, Inc., Chuo-ku, Tokyo, Japan No Drawing. Filed Aug. 5, 1968, Ser. No. 749,960 Claims priority, application Japan, Aug. 10, 1967, ll/50,928; Apr. 17, 1968, 43/25,239 Int. Cl. B44d 1/44; D06n 3/04, 3/06 U.S. Cl. 117-63 Claims ABSTRACT OF THE DISCLOSURE A process for the manufacture of an artificial leather, which comprises a first step wherein a fluff-holding highmolecular-weight polymer is applied to the surface of a fibrous sheet material and the surface of said fibrous sheet material is contacted with a smooth surface heated to a temperature not lower than the glass transition point of fibers that constitute said fibrous sheet material but not higher than the melting point of said high-molecularweight polymer to thereby hold down the fluffs on the surface of the sheet material and a second step wherein a binder solution and subsequently a coating synthetic resin solution are applied to said fibrous sheet material and thereafter coagulated.

This invention relates to a process for the manufacture of an artificial leather which is tenacious, and has a smooth surface and a good feel.

Various methods have been proposed heretofore to produce an artificial leather. An artificial leather comprising a fibrous sheet-like material as a substrate has been known to be relatively close to natural leather in structure and feel, and an artificial leather of this kind having a smooth surface has been manufactured hitherto by the following three methods. Incidentally, the term fibrous sheet-like material excludes knitted and woven goods.

(1) To inter-pose a knitted or woven article between a coating and a fibrous sheet-like material.

(2) To slice or buff the surface of a fibrous sheet-like material to remove the unevenness of the surface. J

(3) To smoothen a non-woven fabric by hot pressing.

According to method (1), however, a continuous density gradient as seen in natural leather cannot be obtained because of the interposition of the knitted or woven fabric. Furthermore, anisotropy peculiar to the knitted or woven article shows itself in the obtained artificial leather, and constitutes a setback against wearing and shoe-making. Method (2) gives a large injury to fibers that constitute the fibrous sheet-like material, and also deteriorates such physical properties of the obtained artificial leather as tenacity. Method (3) makes possible the smoothening of the leather, but in order to hold down fluffs on the surface of the fibrous sheet-like material, it is necessary to apply hot pressing at a temperature above the softening point of a resin used as a binder. The binder resin in the fibrous sheet-like material, when heated at that temperature, softens and flows, and is finally agglutinated. This markedly impairs the feel of the obtained artificial leather.

The prior method of producing an artificial leather containing a fibrous sheet-like material comprises applying a binder resin to a fibrous sheet-like material, coagulating and drying it, subjecting it to a smoothening treatment, and thereafter applying a coating thereto. According to this method, the sheet-like material cannot be integrated with the binder resin, and therefore, these two layers are only weakly bonded with each other. Furthermore, the method cannot give a structure having a conice tinuous density gradient. Hence, the obtained artificial leather is not good in feel and capability of being made into shoes.

An object of this invention is to provide a process for manufacturing by a series of simple steps a tenacious artificial leather having a smooth surface and excellent feel, which process is free from the above-mentioned defects.

Another object of the invention is to provide a process for manufacture of improved artificial leather having a continuous density gradient wherein a coating synthetic resin is integrated with a substrate to provide a good bonding between these two layers.

These objects of the invention can be achieved by a process for manufacture of an artificial leather which comprises a first step wherein a solution or emulsion of a high-molecular-weight polymer is applied to the surface of a fibrous sheet-like material and the so treated sheetlike material is contacted with a heated smooth surface to thereby hold down fluifs on the surface and a second step wherein a binder solution is applied to the so treated fibrous sheet-like material, which is then coated with a coating solution of a synthetic resin, followed by coagulation. It is preferable that in the second step of the process, the coating synthetic resin solution dissolved in a solvent Which is the same as, or compatible with, the solvent of said binder solution is applied to the fibrous sheet material while said binder solution is not substantially coagulated, and then both the binder and the coating synthetic resin are coagulated simultaneously.

The first step of the process of the invention involves applying a solution or emulsion of a high-molecularweight polymer to the surface of a fibrous sheet material (to be referred to as a fluff-holding high-molecular-weight polymer), and contacting the treated sheet material intimately with a heated smooth surface after the solvent or dispersion medium of said high-molecular-weight polymer has been dried or While it is still in an undried state whereby treatment is carried out at a temperature such as will not cause the degeneration and deterioration of fiuff-holding high-molecular-weight polymer impregnated in the fibrous sheet material.

Smoothening by the heated surface may be effected after the solvent or dispersion medium of the fluff-holding high-molecular-weight polymer has been dried up, but a larger effect of holding down fluffs can be obtained if it is carried out in a state where the solvent or dispersion medium remains. If the fluff-holding high-molecularweight polymer is not a thermoplastic polymer, it cannot give a sufficient effect of holding down fluifs when it is dried up.

In the conventional manufacture of a synthetic leather containing a fibrous sheet material as a substrate, a surface coating layer or surface film is formed on the surface of a fibrous sheet material obtained by needle punching a fibrous Web produced by a card, garnett or random webber which is laminated or not, or by fulling or a similar means without punching. At this time, fiuffs on said fibrous sheet material give trouble in coating the material to obtain a smooth surface, make it impossible to obtain a product having a smooth surface, and deteriorate the quality of the product.

These defects, although to a varying degree, are also seen in a fibrous sheet material containing no binder, a fibrous sheet material obtained by slicing to a desired thickness or a fibrous sheet material obtained by stitching a web.

To remove such defects, attempts have been made heretofore to form a surface film, impregnate a binder of a higher concentration into a fibrous sheet material, or effect a fiuif burning or bufiing. These methods complicate 3 the process, increase the cost of production, and make it difficult to obtain a thin, pliable artificial leather, and the obtained product becomes rubbery. They undergo defects such as the spoiling of beauty of a product owing to the occurrences of acute-angular creases, easy occurrence of stripping between layers, worsening of drapeability and moisture-permeability or re-occurrence of fluffs by a complicated procedure such as an artificial leather making. Consequently, such methods are not preferable as a fluffholding processing of a substrate for an artificial leather.

A method wherein a fibrous sheet material is contacted with a heated roller to melt-adhere the flutfs on the surface has been proposed to hold down fiuffs occurring by needle-punching of said fibrous sheet material consisting of a thermoplastic synthetic resin. This method may pose no problem in making a carpet, but is not preferable in the case of an artificial leather substrate. Th surface layer of said fibrous sheet material is filled with melt-adhered fibers. This not only worsens the air-permeability, moisture-permeability and pliability of the substrate, but also deteriorates the binder and the fibers on the surface layer, thus lowering the strength of the substrate.

The first step of the process of the invention has for its object the provision of a smooth fibrous sheet material free from these defects.

The fibrous sheet material used in the practice of the invention consists essentially of fibers. Usable fibers are natural fibers, regenerated fibers, synthetic fibers or blends of these, but it is necessary to select such fibers as are insoluble in the solvent for the resin and a coagulating liquid for the resin and are not subject to deterioration in strength. Such fibers should preferably have a size of 0.5 denier, and a length of 10 mm. to 100 mm.

The method of making fibers into a shet includes a wet method such as a paper-making process and a dry method such as a process wherein a web is prepared by means of a card or random webber and a binder resin is applied to the web, or a process wherein a web is subjected to a physical treatment such as chain stitch needling. In the present invention, the latter-mentioned dry method is employed. In particular, to retain a predetermined thickness as leather and improve the cohesion of a fibrous sheet material in the direction of its thickness, a method is preferably employed wherein the fibrous sheet material is needle-punched to form a felt. The so obtained sheet material should preferably have a weight per unit area of 150 g./m. to 1,000 g./m. The type and number of a needle to be used vary according to fibers, but usually Nos. 32-42 needles (standard of Torrington Co., U.S.A.) are used. The number of needle penetration per square centimeter and the needle penetration depth are regulated according to the type of fibers and number of a needle used.

As the fluff-holding high-molecular-weight polymer to be applied to the surface of a fibrous sheet material with a view to smoothening the surface in the firs-t step of the invention, there can be used natural rubber, synthetic rubber such as acrylonitrile-butadiene copolymer, synthetic polymers such as poly (acrylic ester), poly (vinyl chloride) and poly (vinyl alcohol), natural high polymers such as starch and casein, and cellulose derivatives such as carboxymethyl cellulose. They may be used either as solution or emulsion. These high-molecular-weight polymers may be thermosetting, but preferably thermoplastic. A solution or emulsion of said high-molecular-weight polymer is applied to a fibrous sheet material by such means as spray coater, gravure, coater and kissing coater. A preferably means is such as is capable of applying it only to the top of the surface.

Said fluff-holding high-molecular-weight polymer is selected according to fibers that constitute a fibrous sheet material, a binder impregnated into the sheet material and a solvent for the binder. If adhesiveness between a surface film and a fibrous sheet material and penetration of the surface film into the sheet material are considered, it is preferable that the fluff-holding high-molecularweight polymer should be soluble in a solvent for a highmolecular-weight polymer, which forms the surface film. By choosing such a fluff-holding high-molecular-weight polymer, the adhesiveness is increased, and integration of the surface film with said sheet material is improved.

An amount of the fluff-holding high-molecular-weight polymer to be coated is determined according to the purpose of using a fibrous sheet material and the shape of fibers that constitute the sheet material, but should preferably be a minimum that can ever effect the intended holding down of fluffs.

In the first step of the process of the invention, a fibrous sheet material to which has been applied an emulsion or solution of the high-molecular weight polymer is contacted with a heated surface, preferably heated to a temperature not lower than the glass transition point of fibers that constitute the fibrous sheet material but not higher than the melting point of said high-molecularweight polymer. As the heated surface, a hot press or cylinder roll is used, but there is no patricular restriction about it. If the heating temperature is below the glass transition point of the fibers of the sheet material, sufficient fluff holding cannot be achieved. On the other hand, when it is above the melting point of said highmolecular-weight polymer, the polymer melt-adheres to the heated surface, and when stripped off, pulls up fibers on the surface of the fibrous sheet material. This results in the occurrence of new fluffs, and is not preferable.

A fibrous sheet material obtained in the first step has a remarkably improved smoothness at the surface, and makes it easy to form a surface film having a uniform thickness and a smooth surface. Furthermore, adhesiveness between the surface film and the fibrous sheet material is enhanced, and the smoothening does not result in spoiling the pliability, moisture-permeability and airpermeability.

The so treated fibrous sheet material is then subjected to a second step compising applying a binder and coating a. synthetic resin solution for the formation of a surface layer. Preferably, in the second step, the coating synthetic resin applied before the binder solution is substantialy coagula-ted, and the binder and the coating synthetic resin are simultaneously coagulated. It is preferred therefore that the binder and the coating synthetic resin should be the same or have the same chemical composition.

Examples of preferable binders and coating synthetic resin for forming a surface layer are thermoplastic resins such as polyamides poly (vinyl chloride), polyacrylonitrile, synthetic rubbers such as a nitrile-butadiene co-polymer and styrene-butadiene copolymer, and polyurethane. These resins may be used in admixture of two or more. They are applied to the fibrous sheet material as a solu tion in a solvent which is non-solvent for fibers that constitute said fibrous sheet material. It is necessary however that the coating synthetic resin for the formation of a surface layer should have a viscosity higher than that of the binder solution. Appropriately, the viscosity of the coating synthetic resin ranges from to 10,000 poises, and that of the binder resin solution, from 0.1 to 100 poises.

It is preferred that a solvent for the binder should be the same, or compatible with, that for the coating synthetic resin. Examples of compatible solvents are dimethyl formamide, diethyl formamide, dimethyl acetamide and dimethyl sulfoxide. It is possible to incorporate into a synthetic resin solution a pigment such as carbon black, a filler such as precipitated calcium carbonate and cellulose powder or a plasticizer according to necessity. In the impregnation of a binder solution intoa fibrous sheet material, it is preferable to get the binder uniformly into an inner layer of the fibrous sheet material with the use of such a squeezing machine as a screen and mangle. Subsequently, a synthetic resin for forming a surface layer is applied to a surface which has been subjected to a smoothening treatment in the first step by means of a reverse roll coater or knife coater in accordance with such a procedure as will not substantially cause coagulation of the binder resin.

In the invention, a coating synthetic resin for forming a surface layer is applied before a binder resin is coagulated, and a liquid-liquid mixing is effected on the interface. As the result, when the binder resin and the coating synthetic resin are simultaneously coagulated thereafter, the fibrous sheet material is integrated with the surface layer to a degree such that they are not separated from each other. To coagulate the binder resin and coating synthetic resin, there are employed a wet method wherein extraction of a solvent is conducted in a liquid having compatibility with the solvent, for instance, in water, and a dry method wherein extraction of a solvent is conducted by such a means as heating. In view of feel and moisture-permeability of a final product, the wet method is preferable. Water-washing, drying and surface finishing treatments after the coagulation step give a leather closely resembling natural leather. The obtained artificial leather may be passed through an embossing machine. To improve the lustre and colour of the surface, such a paint as a nitrocellulose lacquer may further be applied.

Furthermore, the application of a coating synthetic resin for forming a surface layer may be made two times or more successively to change the structure of the surface film sequentially. One embodiment of the invention involves a first step of applying to a sheet material a highmolecular-weight polymer which is insoluble in solvents for a binder resin and a coating synthetic resin but is soluble in a coagulating liquid or washing liquid, a second step of applying the binder resin and coating synthetic resin, and a subsequent step of coagulation and/ or water-wash ing. In this embodiment, the high-molecular-weight polymer applied to the fibrous sheet material is dissolved and removed to prevent excessive bonding between the binder and the fibers and thereby to make a final product pliable.

The artificial leather obtained by the invention is free from surface defects that are caused by fluffs as in the conventional products, and has a good smoothness. Furthermore, cohesion between the surface resin layer and the fibrous sheet material of the obtained artificial leather is large because the binder and coating synthetic resin are simultaneously coagulated and are integrated with the sheet material. As part of the resin in the surface layer is penetrated into the fibrous sheet material, there is provided a density gradient of the coating synthetic resin and binder resin from the surface to the back side. Therefore, like natural leather, the obtained artificial leather has a structure wherein there is a continuous density gradient from a flesh side to a grain side layer, and both layers are integrated with each other. Furthermore, in the artificial leather of the invention, there is more resin near the surface of the fibrous sheet material, and fibers near the surface are prevented from a free movement. In the processing of such an artificial leather in a stretched state, therefore, traces of punching do not come up on the surface. This is advantageous in the toe lasting of a shoe-making process, for instance.

In the invention, penetration of a coating synthetic resin into a fibrous sheet material is promoted by a binder solution. Much coating synthetic resin is penetrated into a substrate. In addition, cohesion between layers is enhanced because both a binder and a coating synthetic resin are simultaneously coagulated.

The following examples are presented to illustrate the invention, and are not intended to be limitative. All parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 AND COMPARATIVE EXAMPLES 1-4 A fibrous sheet material having a weight per unit area of 250 g./m. Was prepared from polyester staples having a denier of 1.5, a length of 35 mm. and the number of crimps of 15 turns/inch by using a cross lapper. The obtained fibrous sheet material was punched with a needle loom using No. 40 needles (standard of Torrington Co., U.S.A.). The number of needle penetration per square centimeter was 500, and the needle penetration depth was 8 mm. A 10% aqueous solution of poly (vinyl alcohol) having a molecular weight of 1500 was applied to the surface of the punched sheet material by means of a spray coater until the take-up of poly (vinyl alcohol) was 5 g./m. calculated as a solid content, uniformly all over the surface. The fibrous sheet material was then passed through a pair of hot rolls heated to 160 C. so that its thickness after hot pressing was 1.0 mm.

One hundred parts of a copolymer consisting of 35 moles of vinyl acetate and 65 moles of vinyl chloride, 20 parts of carbon black, 50 parts of dioctyl phthalate as a plasticizer and 35 parts of calcium carbonate were dissolved into dimethyl formamide, and there were prepared a solution having a solid concentration of 10% and a viscosity of 5 poises and a solution having a solid concentration of 30% and a viscosity of 300 poises. The 10% solution was used as a binder, and the 30% solution was used for forming a coating. The fibrous sheet material was immersed into the 10% binder solution, and squeezed by a mangle until the take-up as a solid content was 50 parts per parts of the fibers. Thereafter, the 30% solution was applied to the smoothened surface by a knife coater with a clearance of 1.5 mm. After impregnation of coating, the so treated sheet material was immersed in water at 20 C. to thereby coagulate both the binder and the coating synthetic resin. Subsequent waterwashing and drying gave an artificial leather which is tough and has a smooth surface and a good feel. The physical properties of the obtained leather are shown together with those of comparative specimens (1), (2), (3) and (4).

The comparative specimens were prepared by the following procedures.

Specimen 1) The smoothening and fluff-holding treatments of the first step of the invention are not conducted. The same binder and coating synthetic resin used in Example 1 are applied to a fibrous sheet material under the same conditions as in Example 1, and are coagulated simultaneously.

Specimen (2) The same binder as used in Example 1 is applied to a fibrous sheet material. It is then subjected to a coagulation, water-washing, and drying treatment. The so treated fibrous sheet material is hot pressed by means of a cal ender roll at C. It is coated with the same coating solution as used in Example 1, followed by coagulation, washing with water and drying.

Specimen (3 The same binder as used in Example 1 is applied to a fibrous sheet material, and the treated sheet material is sliced from both sides so that its thickness may be 1.0 mm. The same coating synthetic resin as used in Example 1 is applied to the fibrous sheet material under the same conditions as in Example 1.

Specimen (4) A binder is applied to a fibmrous sheet material, and the sheet material is sliced from both sides so that its thickness may be 0.8 mm. A 0.2 mm. thick woven fabric obtained from yarns of 40 count composed of 30 parts of polyester and 70 parts of cotton is superposed on the fibrous sheet material with the use of a synthetic resin having the same composition as the coating synthetic resin. Thereafter, a coating synthetic resin is applied to the Woven fabric under the same conditions as in Example l.

synthetic resin solution as in Example 2 was used. The fibrous sheet material was treated in the same manner as TABLE 1 Defects Cohesion Shape owing to between Tenacity Pliability retention flufis smoothness layers Examplel High Good".-. Good-.. None Good Good. Comparative Interdo do Many... Bad Do.

Example 1. mediate. Comparative High Bad Bad Some Good Bad.

Example 2. Comparative Low Good Bad None Somewhat Bad.

Example 3. bad. Comparative High Somewhat Bad ..do Good Bad.

Example 4. bad.

EXAMPLE 2 111 Example 2 with the use of these solutions. An arti- A prepolymer prepared from diphenylmethane-4,4-diisocyanate and polyethylene adipate having a molecular weight of 2,000 was chain-extended by butanediol. The obtained polyester polyurethane was dissolved into dimethyl formamide to form a 15% solution having a viscosity of 20 poises. A fibrous sheet material which had been subjected to the same first step as in Example 1 was immersed in this solution, and squeezed by a mangle until the take-up as a solid content was 40 parts per 10 parts of the fibrous, followed by immediate smoothening treatment. A coating synthetic resin solution was applied to the so treated fibrous sheet material. This coating synthetic resin solution was prepared by mixing 100 parts of the polyester polyurethane, parts of carbon black and 60 parts of precipitated calcium carbonate with dimethyl formamide. After the impregnation and coating, the binder solution and the coating synthetic resin solution were coagulated simultaneously by immersion in water at C. The treated fibrous sheet material was then washed with water and dried. It was pressed with a metal roll having an embossed pattern, and an artificial leather hav ing a leather-line embossment on the surface was obtained. The obtained leather had a smooth surface and a good feel like the product of Example 1.

EXAMPLE 3 A fibrous sheet material having a weight per unit area of 400 g./m. was prepared by a random webber from nylon 6 staples having a denier of 3, a length of 51 mm. and the number of crimps of 15 turns per inch. The fibrous sheet material was punched by a needle loom. The used needles were No. 36 (standard of Torrington Co., U.S.A.). The number of needle penetration per square centimeter was 400, and the needle penetration depth was 10 mm. A solution of a latex (Hycar 1571, The Japanese Geon Company) of an acrylonitrile-butadiene copolymer was sprayed onto the extreme surface of the treated fibrous sheet material until the take-up of the solution was 5 g./m. as a solid content, all over the fibrous sheet material uniformly. The sheet material was dried with the use of a hot air drier at 100 C. The dried product was passed through a pair of calender rolls heated to 160 C. to adjust the thickness of a final product to 1.0 mm.

A polyurethane prepolymer was prepared by reacting 2 moles of polytetrahydrofurane having a molecular weight of 2080 with 3.2 moles of a mixture of 2.4 moles of tolylene diisocyanate and 2,6-tolylenediisocyanate. It was reacted with an equimolar amount of hydrazine hydrate in dimethyl formamide to form a polyurethane solution. The polyurethane solution was mixed with 40 parts, based on parts of the solid content of pulyurethane, of an acrylonitrile-butadiene copolymer consisting of 35 moles of acrylonitrile and moles of butadiene, and the resulting mixture was diluted with dimethyl formamide to form a solution having a solid con centration of 10% and a viscosity of 5 poises. This solution was used as a binder solution, and the same coating ficial leather having a smooth surface and a good feel was obtained.

EXAMPLE 4 The needle-punched fibrous sheet material used in Example 3 was immersed in a 10% aqueous solution of poly (vinyl alcohol) having a degree of polymerisation of 500 and a degree of acetylation of 13 mole percent, and squeezed by a mangle until the take-up of a solid content of poly (vinyl alcohol) reached 10% based on the weight of the fibers. A 25% solution of a latex of an acrylonitrile-butadiene copolymer was sprayed onto the so treated fibrous sheet material so that the take-up of the copolymer as a solid content might be 10 g./m. all over the surface of the sheet material uniformly. The sheet material was dried by a hot air drier at C., and passed through a pair of calender rolls heated to C. to smoothen its surface. The binder solution and the coating synthetic resin solution used in Example 2 were successively applied to the fibrous sheet material. Immediately thereafter, the solvent was extracted in water at 20 C. to effect coagulation. The sheet maerial was then washed for 30 minutes in a warm water at 30 C., with the simultaneous extraction of the poly (vinyl alcohol). It was dried for 20 minutes in a drier at 100 C. An artificial leather having a smooth surface and a good feel was obtained.

EXAMPLE 5 The needle-punched fibrous sheet material of Example 1 was subjected to the same fluff-holding treatment as in Example 1. The treated sheet material was immersed in a 20% solution of polyurethane in dimethyl sulfoxide used in Example 2, and squeezed by a mangle so that the solid take-up might be 20 parts as against 100 parts of the fibers. Immediately thereafter, the felted surface was coated with a 30% solution of 100 parts of polyurethane, 50 parts of precipitated calcium carbonate and 30 parts of carbon black in dimethyl formamide, and subjected to a coagulating step in water at 20 C. Subsequent water- Washing and drying gave an artificial leather which had a smooth surface and a good feel like the products of Examples 1-3.

We claim:

1. A process for manufacturing an artificial leather, which comprises (1) applying a fluff-holding high molecular weight polymer to the surface of a fibrous sheet material, (2) contacting the surface of the resultant fibrous sheet material with a smooth surface heated to a temperature not lower than the glass transition point of the fibers of the fibrous sheet material and not higher than the melting poin of the high molecular weight polymer to hold down the fiufis on the surface of the fibrous sheet material, (3) applying a thermoplastic resin binder solution to the thus-treated fibrous sheet material, (4) applying a coating synthetic resin solution whose solvent is the same as or compatible with the solvent of the binder solution to the product of Step 3, and (5) simultaneously coagulating the binder and coating synthetic resin with a liquid which is compatible with the solvents of the 9 binder solution and Coating synthetic resin solution and is non-solvent for the binder and coating synthetic resin.

2. The process according to claim 1 wherein the fluff holding high molecular weight polymer is at least one selected from the group consisting of natural rubber, syn thetic rubber, polyacrylic ester, polyvinyl chloride, poly vinyl alcohol, starch, casein and carboxymethylcellulose.

3. The process according to claim 1 wherein the binder is at least one selected from the group consisting of polyamide, polyvinyl chloride, polyacrylonitrile, an acrylonitrile-butadiene copolymer, a styrene-butadiene copolymer and polyurethane.

4. The process according to claim 1 wherein the coating synthetic resin is at least one selected from the group consisting of polyamide, polyvinyl chloride, polyacrylonitrile, an acrylonitrile-butadiene copolymer, a styrenebutadiene copolymer and polyurethane.

5. The process according to claim 1 wherein the viscosity of the coating resin solution is higher than that of the binder solution.

6. The process according to claim 1 wherein the fluffholding high molecular weight polymer is in the form of a solution.

7. The process according to claim 1 wherein the fluffholding high molecular weight polymer is in the form of an emulsion.

8. The process according to claim 1, wherein the binder solution is a solution of a synthetic rubber.

9. The process according to claim 1, wherein the binder solution is a solution of a polyurethane.

10. A process for the manufacture of an artificial leather Which comprises a first step wherein a fluff-holding high molecular weight polymer is supplied to the surface of a fibrous sheet material and the surface of said fibrous sheet material is contacted with a smooth surface heated to a temperature not lower than the glass transition point of fibers that constitute said fibrous sheet material but not higher than the melting point of said high molecular weight polymer to thereby hold down the fluifs on the surface of the sheet material and a second step wherein a binder solution and subsequently a coating synthetic resin solution are applied to said fibrous sheet material and thereafter coagulated, followed by washing with water whereby the flulT-holding high molecular weight polymer applied in the first step is dissolved.

References Cited UNITED STATES PATENTS 2,944,294 7/1960 Bourbeau 117-63 3,000,757 9/1961 Johnston et al. 1l763 3,067,482 12/1962 Hollowell 11763X 3,100,721 8/1963 Holden 117135.5 3,190,766 6/1965 Yuan 117l35.5 3,369,925 2/1968 Matsushita et al. 117-63 2,819,981 l/l958 Schornstheimer 117-l35.5X

WILLIAM D. MARTIN, Primary Examiner W. R. TRENOR, Assistant Examiner US. Cl. X.R. 

